The problem of feeding electrical cables into ducts or conduits has been known for a long time. A presentation of this problem can be found in the published patent application WO 2010/111801.
Presently this problem has been solved in particular by devices such as those presented for example in publications U.S. Pat. No. 2,556,484 (published on Jun. 12, 1951) and U.S. Pat. No. 6,722,603 (published on Apr. 20, 2004). The device described in document U.S. Pat. No. 2,556,484 presents a wire-pulling device, in particular for laying electrical cables in a building, comprising a frame, a spool of a flexible elongate element wound into a coil, and means for unwinding this element and advancing the same into a section of a duct of an electrical facility, said spool being mounted on a rotary drum driven by a mechanism, said drum having a U-shaped cross-section in which the flexible member is arranged, the flexible elongate member being fed into a rigid guide member arranged tangentially relative to the periphery of said rotary drum. Although this device seems to describe an apparatus that can operate, the use of this apparatus must show great difficulties. Because, when pushing the flexible element into a duct, the pushing force due to the knees and frictions of said element will increase, and the flexible element will tend to create convolutions towards the outside, which will rest on the rollers and on the housing until the drive motor will block. Moreover, this device will require the presence of at least two operators.
Document U.S. Pat. No. 6,722,603 describes a relatively simple device that makes no statement relating to the reaction force at the moment of the feeding of the flexible element into a duct. This device also requires the presence of two operators, one to hold the device and a second one to fasten the wires.